Skid steer vehicle

ABSTRACT

A skid steer vehicle comprising a body having a front end and a rear end and ground engageable propulsion wheels disposed on opposite sides of the body, each propulsion wheel being carried on an outer end of a stub axle which is housed, so as to be rotatable about an axis of rotation, in a stub axle housing member mounted on the body wherein each stub axle housing member is provided with a carrier member which is mountable on the body in a selected one of a plurality of any angular positions about a reference axis, the stub axle housing member being positioned relative to the carrier member so that said axis of rotation is disposed eccentrically relative to said reference axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to three copending application of thepresent invention, filed on even date herewith, namely Ser. No.7/657,569, entitled "SKID STEER VEHICLE" now abandoned; Ser. No.7/657,678 "SKID STEER VEHICLE" now abandoned; and Ser. No. 7/657,648,entitled "LOADER VEHICLE", all of which are assigned to the assignee ofthe present invention.

BACKGROUND TO THE INVENTION

This invention relates to a skid steer vehicle, hereinafter referred toas "of the kind specified" comprising a body having a front end and arear end and ground engageable propulsion wheels disposed on oppositesides of the body, each propulsion wheel being carried on an outer endof a stub axle which is housed, so as to be rotatable about an axis ofrotation, in a stub axle housing member mounted on the body.

An inner end of each stub axle may have a driven wheel thereon which isdriven by a flexible loop from a driving wheel driven by a motor or theinner end of each stub axle may be driven by other means such as aseparate motor for each stub axle.

An object of the invention is to provide a new and improved skid steervehicle of the kind specified.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, we provide a skidsteer vehicle of the kind specified wherein each stub axle housingmember is provided with a carrier member which is mountable on the bodyin a selected one of a plurality of any angular positions about areference axis, the stub axle housing member being positioned relativeto the carrier member so that said axis of rotation is disposedeccentrically relative to said reference axis.

Preferably, the carrier member and the body are provided withcooperating guide means which guide the carrier member for rotationabout said reference axis.

By virtue of said eccentric disposition of the axis of rotation, thedistance between the driven wheel and the driving wheel may be adjustedthereby permitting adjustment of the wheel base, the ground clearanceand the height of the centre of gravity of the machine; where the stubaxles are driven by flexible loops, a flexible loop of appropriatelength is provided. In addition, a flexible loop of a given length maybe tensioned.

The body may be provided with an engine, two pairs of ground engageablepropulsion wheels disposed on opposite sides of the body, a hydraulicdrive means including first and second variable displacement pumpsdriven by the engine and operatively connected to first and secondhydraulic motors disposed on opposite sides of the body, each pump beingdrivably connected to two ground engageable propulsion wheels of anassociated one of said pairs of wheels on the associated side of thebody by first and second endless loops each of which is engaged with adriving wheel driven by the pump and with a driven wheel connected to anassociated one of the ground engageable wheels of said pair andpropulsion control means whereby the hydraulic drive means can drive thepair of wheels on one side of the vehicle at the same or a differentspeed and/direction from the pair of wheels on the other side of thevehicle to propel and steer the vehicle.

The body may be provided with a longitudinally extending loop casecompartment on each side of the vehicle, each loop case compartmenthaving a transversely inner wall and a transversely outer wall joined bytop and bottom walls and end walls, said stub axle housing member ormembers being mounted on the outer wall with said driven wheel or wheelsdisposed within said compartment.

Preferably, two stub axle housing members are provided on each side ofthe vehicle and each of said housing members are mounted on said outerwall with said driven wheels disposed within the compartment with saiddriving wheels disposed within the compartment therebetween with saidloops engaged with respective driving and driven wheels.

The outer wall may be provided with a circular opening for the or eachhousing member to provide one of said co-operating guide means.

From a second aspect, the present invention relates to a skid steelvehicle, hereinafter referred to as "of the second kind specified",comprising a body having a front end and a rear end, ground engageablepropulsion wheels disposed on opposite sides of the body, eachpropulsion wheel being driven by a flexible loop from a driving wheeldriven by a motor.

A further object of the invention is to provide a new and improved skidsteer vehicle of the second kind specified.

According to a second aspect of the present invention, we provide a skidsteer vehicle of the kind specified or the second kind specified whereinthe driving wheel or wheels are carried on an output shaft of a motorand are unsupported by means independent of the motor.

The body may be provided with a longitudinally extending loop casecompartment on each side of the vehicle, each loop case compartmenthaving a transversely inner wall and a transversely outer wall joined bytop and bottom walls and end walls.

In both the first and the second aspects of the invention, each pump maybe mounted on the inner or the outer wall of an associated loop casecompartment with the driving wheel or wheels disposed within theassociated loop case compartment.

The driving wheel or wheels are preferably carried on an output shaft ofthe associated motor and are unsupported by the other wall of theassociated compartment.

The output shaft of each motor may be supported at an outer part thereofby an outer bearing carried by a bracket fastened to the respectivemotor body.

The bracket may be provided with openings to permit of passage of saidloop or loops.

The driving wheel or wheels may be provided on a sleeve member whichreceives the output shaft of the associated motor therein at one end, aninner bearing being provided between the sleeve and the body of themotor.

Preferably, the outer bearing is provided between the bracket and saidsleeve.

A brake member may be carried by the output shaft outwardly of saidsleeve.

The outer wall of each loop case compartment may be provided with anopening in way of the motor and driving wheel or wheels to permit ofmanipulation of a loop into driving relationship with a driving wheeland driven wheel.

The brake member may be disposed outwardly of the part of the outer wallof the loop case compartment at locations spaced from said motor and aremovable extension housing may be provided to enclose the brake member.

The or each endless loop may comprise a chain such as a roller chain andthe driving and driven wheels may comprise sprocket for engagement withthe chain.

Alternatively, the or each endless loop may comprise a toothed oruntoothed belt and the driving and driven wheels appropriate pulleys.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way of examplewith reference to the accompanying drawings wherein:

FIG. 1 is a perspective view of a skid steer vehicle embodying theinvention,

FIG. 1a is an enlarged fragmentary view of part of FIG. 1 to an enlargedscale,

FIG. 2 is a side elevation of the vehicle of FIG. 1 but showing theopposite side thereof to that shown in FIG. 1,

FIG. 3 is a section on the line 3--3 of FIG. 2,

FIG. 4 is a section on the line 4--4 of FIG. 2,

FIG. 5 is a front elevation of the vehicle of FIG. 1 with part omittedfor clarity,

FIG. 6 is a graphical representation of the swash plate angle controlmember regime for different propulsion control member positions,

FIG. 7 is a diagrammatic illustration of a mechanical linkage for use inthe vehicle of FIG. 1,

FIG. 8 shows part of a hydraulic linkage for use in the vehicle of FIG.1,

FIG. 9a is a diagrammatic plan view of a propulsion control lever foruse with the linkage of FIG. 8,

FIG. 9b is a diagrammatic cross-section on the line 9b-9b of FIG. 9a,and

FIG. 10 is a diagrammatic illustration of an alternative form ofmechanical linkage utilising flexible cables.

FIG. 11 is a fragmentary transverse cross-section, to an enlarged scale,to the vehicle of FIG. 1 showing a stub axle housing assembly,

FIG. 12 is a fragmentary transverse cross-sectional view, to an enlargescale, to the vehicle of FIG. 1 showing a motor assembly,

FIG. 13 is a fragmentary perspective view showing part of the operator'scompartment of the vehicle of FIG. 1,

FIG. 14 is another perspective view of part of the operator'scompartment shown in FIG. 13 but taken from a different viewpoint, and

FIG. 15 is a diagrammatic perspective view showing an alternative, andpreferred operator restraint to that shown in FIGS. 13 and 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS General Layout

Referring now to the drawings, a skid steer loader vehicle 10 comprisesa body 11 having a front end 12 and a rear end 13. The body 11 isprovided with ground engageable propulsion means 14 comprising a pair offront wheels 15 disposed forwardly of a pair of rear wheels 16. Thevehicle 10 is propelled in a straight line forwardly or rearwardly bydriving all four wheels or, to steer the vehicle, by driving the wheels15 and 16 on one side at a different speed and/or direction than thoseon the other side. Such skid steer loaders have a high degree ofmanoeuvrability and to facilitate skid steering and in particular, forexample, the ability of the vehicle to turn about a central axis of theground engageable propulsion means the wheel base is made, in thepresent example, slightly shorter than the track of the vehiclealthough, if desired, the wheel base may be the same or longer than thetrack if desired.

The wheels 15, 16 are carried on stub axles 17 which project outwardlyfrom a pair of transversely spaced side members 18, 19 of the body 10and which extend fore and aft of the vehicle. Between the side members18, 19 is a transmission compartment 20 which houses a transmission 21,hereinafter to be described in more detail, whilst above and forwardlyof the transmission compartment 20 is an operator's compartment 22 inwhich is provided an operator's seat 23, manually operable propulsioncontrols 24 for controlling the speed, selecting forward and reversemovement, and steering the vehicle and manually operable loader controls25 for controlling a loader arm and material handling implement ashereinafter to be described.

The operator's compartment 22 is also defined by a pair of upstandingmembers 26, 27 which extend upwardly from the side member, 18, 19 onopposite sides of the vehicle and by a roof 28 which extends forwardlyand adjacent its forward end is supported by posts 29.

A wire mesh screen 30 is provided on one side 31, of the operator'scompartment 22 for protection of an operator, whilst the other side, 32of the operator's compartment is unobstructed and provides an accessopening 33 whereby an operator can enter and leave the operator'scompartment 22.

Behind the transmission compartment 20 and operator's compartment 22 isprovided an engine compartment 34 in which an engine 35 of any suitabletype is housed. In the present example the engine is an air-cooleddiesel engine but any other suitable engine may be provided.

Loader Boom Assembly

The vehicle is provided with a loader arm boom assembly 40 which isdisposed adjacent the one side 31 of the operator's compartment 22. Theloader arm assembly 40 comprises a lift arm assembly 41 which has apivot member 42 projecting from an inner end 43 of the lift arm assembly41 and extends transversely of the body and is pivotally mounted on thebody by pivotal mounting means 44, 45 provided on the upstanding members26, 27 respectively. The lifting arm assembly 41 has an implementcarrying member 46 which projects form an outer end 47 of the liftingarm assembly and extends transversely across the front end of the bodyand has a material handling implement 48 carried thereby so as to bedisposed forward of the front end 12 of the body 11. In the presentexample the implement 48 is an earth moving bucket 49 although ifdesired other material handling implements may be provided, such asforks.

The pivotal mounting means comprise a pivot boss 44a welded in anaperture provided in an inner plate 27a of the upstanding member 27 anda pivot pin 45 is fixed therein. At its other end the pivot pin 45 isfixed in a further pivot boss 44b which is welded in an aperture in aninner plate 26a of the upright 26 and a downwardly inclined part 28a ofthe roof plate 28.

At its free end the pivot member 42 has a bearing housing 42a weldedtherein and the housing 42a carries a bush to rotatably mount the pivotmember 42 on the pivot pin 45. At its other end the pivot member 42 hasa further bearing housing 42b in the form of a bush welded in an openingformed in the pivot member 42 where it merges into a major part 55 ofthe lift arm assembly 41 and the bearing housing 42b again houses asuitable bearing bush to pivotally mount the pivot member 42 on thepivot pin 45. The inner plate 26a is cut away in this region, as shownat 26'a in FIG. 1a, to accommodate the boom assembly.

The lift arm assembly 41, pivot member 42 and implement carrying member46 are formed as a unitary member by bending a steel tube to the desiredshape. It will be seen that the lift arm assembly 41 comprises a majorpart 55 which extends generally rectilinearly from the inner end 43towards the outer end 47 and a minor part 56 which extends generallydownwardly and forwardly relative to the main part 55 and is disposedbetween the main part 55 and the implement carrying member 46. As bestshown in FIGS. 4 and 5 an intermediate part 57 is provided between themain and minor parts 55, 56 which is inclined forwardly and transverselyinwardly so as to position the minor part 56 within the front wheels 15and in front of the operator's compartment 22.

A hydraulic lift ram 58 is pivotally connected between a bracket 59welded to the lift arm assembly 41 and the upstanding member 26 about anaxis indicated at 60. The pivotal connection of the lift ram 58 to theupright 26 at the axis 60 comprises a pivot pin 60a which is fixed inpivot bushes 60b welded in openings provided in the inner plate 26a, andan outer plate 26b and a further plate 26c of the upstanding member 26.The cylinder of the ram 58 is pivotally mounted on the pivot pin 60a.The lift ram 58 when actuated is adapted to raise and lower the lift armassembly 41 between a lower position shown in FIGS. 1 to 4 in full lineand a raised position shown in chain dotted line in FIG. 2.

An implement levelling link is indicated generally at 61 and comprises afirst link 62 which comprises a bar 63 pivotally connected to theupstanding member 26 about an axis 64 and connected to a ram 65 from acylinder 66 of which a piston rod 67 projects forwardly and is pivotallyconnected to one end of a first level 68. The pivotal connection of thefirst link 61 comprises a pivot pin 64a fixed in pivot bushes 64b weldedin apertures in the inner and outer members 26a, 26b respectively whilstthe bar 63 is pivotally mounted on the pivot pin 64a.

The first lever 68 is pivotally mounted on the lift arm assembly 41 by apivot member 69 and is connected by a torque tube 70 to a second lever71 which is pivotally connected at its outer end 72 to a second, fixedlength link 73 which is pivotally connected to the bucket 49 as shown at74.

The respective positions of the axis of pivot of the lift arm assembly41 provided by the pivot pin 45 and the connection of the implementlevelling link to the upstanding member 26 at axis 64 together with thelength of the first and second levers 68, 71 and the position of pivotalconnection of the second link 73 to the bucket 49 at 74 together withthe position of pivotal connection of the bucket 49 to the implementcarrying member 46 at 75 is arranged so as to provide a linkage whichensures that the orientation of the bucket 49 relative to the body ispreserved irrespective of the angular position of the lift arm assembly41 so long as relative movement does not occur between the piston rod 67and cylinder 66.

When it is desired to pivot the bucket upwardly, i.e. cause it to rotateabout the axis 75 in a clockwise direction as viewed in FIG. 2, fluid issupplied to the cylinder 65 to act on the larger diameter side of thepiston therein so as to force the piston rod 67 out of the cylinder 65so that the above described linkage causes the desired clockwisemovement of the bucket 49. Such movement is generally required inoperation to lift or tear out earth and hence is known as "tear out"movement. Because the fluid is operative upon the whole cross-sectionalarea of the piston a relatively high power action is provided in thisdirection.

When it is desired to rotate the bucket in an anti-clockwise directionas shown in FIG. 2, commonly known as "dumping" then fluid is suppliedto act on an annular surface of the piston surrounding the piston rod 67so that a smaller cross-sectional area is acted upon and therefore afaster, although less powerful action, is provided.

At the front end 12 of the side member 18 there is provided an abutmentsurface 76 provided by a bar 77 welded to a cam plate extension 78 ofthe side member 18. The bar 77 is adapted to abut a flanged roller 79rotatably mounted on a spigot 80 projecting from the free end of theimplement carrying member 46. The abutment surface 76 comprises a lower,generally vertical surface part 81 and a forwardly and upwardly inclinedpart 82, the surface parts 81 and 82 being contoured to co-operate withthe roller 79 as the lift arm assembly 41 approaches its lowermostposition and to prevent rearward displacement of the free end of theimplement carrying member 46 when in such a lower position, for example,when driving a vehicle forwardly to load the bucket 49. If desired theabutment surface 76 may be extended upwardly so as to support the member46 over a greater height.

From the foregoing it will be seen that boom assembly 40 extendsforwardly from a position adjacent the rear end of the body 11 alongsidethe one side 31 of the operator's compartment 22 whilst the other side32 is unobstructed so that an operator can gain access to thecompartment through the access opening 33.

By providing the axis of pivot of the lift arm assembly 41 adjacent thetop rear corner of the operator's compartment the operator is providedwith the ability to lift the bucket to a relatively great height and atthe same time provide the bucket with good reach and the vehicle with astability. For example, the axis of pivot of the lift arm assembly isapproximately 1.5 m above the ground in the example illustrated, whilstthe distance between the axis of pivot of the lift arm assembly and theaxis of pivot of the bucket about the axle 75 is approximately 2.5 m.Hence the vehicle has a total lift of approximately 3 m and over thewhole of this range of lift the pivotal connection 75 to the bucket liesforwardly of the front end 12 of the vehicle.

Propulsion and Loader Controls

The transmission 21 comprises a pair of conventional swash platehydrostatic pumps 90, 91 the output of which is sent, in conventionalmanner, to a conventional hydrostatic motor 92. In this example therearmost pump 90 provides a feed to the motor 92 on the left-hand sideof the vehicle whilst pump 91 provides feed to the corresponding pump,not shown, on the right-hand side of the vehicle.

The pumps 90, 91 each have an input member 93, 94 respectively which arerotatable about spaced parallel axes which extend perpendicular to afore and aft axis of the vehicle and which lie in a substantiallyhorizontal plane.

The input members 93, 94, in the present example, control the angle ofthe swash plates of their associated hydraulic pump through theintermediary of a hydraulic servo mechanism in-built into the hydraulicpump in conventional manner. If desired, however, the input members 93,94 may directly mechanically actuate the angle of the swash plates againin conventional manner.

The vehicle is provided with a suitable linkage to connect the manuallyoperable propulsion control means 24 to the input members 93, 94 inorder to achieve a desired regime of swash plate angle control. Such aregime is illustrated in FIG. 6 which shows the desire swash plate angleand hence desired input member 93, 94 positioned for different positionsof propulsion control member angular position. The graphicalrepresentation of FIG. 6 assumes that the propulsion control member 95is, in each angular position moved to fullest extent possible but thesame pattern of swash plate control would be achieved for lesser amountsof movement in any particular direction although the extent of movementof the swash plates of each pump would be correspondingly reduced.

When the control member 95 is moved to its fully forward position, i.e.parallel to the fore and aft direction of the vehicle (referred to inFIG. 6 as 0°) both input members 93, 94 are rotated, in the exampleillustrated, in a clockwise direction as viewed in FIG. 2 or FIG. 7 soas to cause forward movement of both the left-hand and right-handpropulsion means.

When the lever is moved 45° to the right (referred to in FIG. 6 as 45°)the linkage causes the input member 94 to adopt a position at which theswash plates deliver no fluid to the motor, i.e. a neutral position,whilst the input member 93 of the swash plate which drives the left-handmotor 92 is maintained in its fully forward position so that the vehicleis caused to turn to the right.

Movement of the member 95 in a direction at 90° to the right (referredto in FIG. 6 as 90°) causes the input member 94 to move to signal theswash plates to move fully to a reverse drive position whilst the inputmember 93 is maintained in its fully forward position and hence thevehicle is caused to turn on its axis.

Movement of the control member 95 to a position 135° to the right causesthe input member 94 to be maintained in its full reverse position whilstthe input member 93 is moved to a neutral position in which no output isproduced by the swash plates.

When the lever 95 is moved in a reverse direction parallel to the foreand aft axis of the vehicle, (referred to in FIG. 6 as 180°) the inputmember 94 is maintained in its full reverse position whilst the inputmember 93 is moved to a full reverse position.

A similar sequence of movements occurs when the lever 95 is moved tocorresponding positions to the left, referred to in FIG. 6 as 225°, 270°and 315°.

A mechanical linkage which aims to provide the above described regime isillustrated in FIG. 7. Each input member 93, 94 is provided with aninput lever 96, 97 respectively and these levers are connected by balljoints at positions A1, A2 to respective links 98, 99 which areconnected by ball joints at A3, A4 to the lower end of an operatinglever 100. The points A1, A2, A3, A4 all lie in a plane which isparallel to and spaced above a plane which contains the axes of rotationof the input members 93, 94.

The operating lever 100 is pivotally mounted to a part 101 of the body11 for universal movement by virtue of a parallelogram linkage 102. Thelinkage 102 comprises a first Hookes joint 103, one yoke 104 of which isfixed to the top end of the operating lever 100 and is also fixed to oneyoke 105 of a second Hookes joint 106, the other yoke 107 of which isfixed to the part 101 of the body. The second yoke 108 of the firstHookes joint 103 is connected by a link 109 to a first yoke 110 of athird Hookes joint 111, the second yoke 112 of which is connected to afirst yoke 113 of a fourth Hookes joint 114, the second yoke 115 ofwhich is fixed to the part 101 of the body. In addition, the second yokeof the third hooks joint 111 carries the propulsion control member 95.Thus movement of the control member 95 in any one of the radialdirections described hereinbefore permitted by the fourth Hookes joint114 will be transmitted by the link 109 and Hookes joint assembly 103,106 to the operating lever 100. The line joining the points B ofconnection of the Hookes joints 106 and 114 to the part 101 of the bodylies parallel to a line joining the parts A1, A2 but in a plane spacedabove the plane containing the parts A1-A4.

Hence movement of the propulsion control member 95 in, for example, theforward direction F parallel to the fore and aft axis of the vehiclewill cause a corresponding movement of the points A3, A4 in the reversedirection Rv which will cause the input members 93, 94 to rotate in aclockwise direction to provide an output to the pumps to cause thevehicle to advance forwardly. Similarly, movement of the control member95 in the reverse direction Rv will cause movement of the points A3, A4in the forward direction F and the corresponding anti-clockwise rotationof each of the input members 93, 94 to provide reverse movement of thevehicle.

Movement of the lever 95 in the direction R, i.e. to the right of thevehicle at right-angles to the fore and aft axis, causes movement of thepoints A3, A4 to the left to cause the input member 93 to rotate in aclockwise direction so that the left-hand ground engageable propulsionunit is driven forwardly whilst the input member 94 is rotated in ananti-clockwise direction to cause the right-hand ground engageablepropulsion unit to rotate in a reverse direction, thereby causing thevehicle to spin on its axis.

If the member 95 is moved to the left in the direction of the arrow L,then the points A3, A4 are moved to the right in the direction of thearrow R thus causing the member 93 to rotate anti-clockwise to cause theleft-hand propulsion unit to provide reverse drive whilst the inputmember 94 is caused to rotate clockwise so that the right-handpropulsion unit is caused to rotate forwards, again causing the vehicleto rotate on its axis but in the reverse direction, i.e. to the left.

Movement of the lever 95 at 45° to any one of the direction describedhereinbefore causes a combination of motions to take place. For example,if the control lever 95 is moved 45° to the right, i.e. midway betweenthe forward and right-hand positions illustrated in FIG. 7, then therewill be a corresponding movement of the points A3 and A4 at 45° midwaybetween the Rv and L directions shown in FIG. 7 having the effect ofmaintaining the input member 94 in its neutral position so that no driveis provided to the right-hand ground engageable propulsion means whilstthe input member 93 is moved fully clockwise to provide full forwarddrive to the left-hand propulsion means, thereby causing the vehicle tosteer to the right. A corresponding combination of motions occurs formovement of the lever 95 at other 45° angles and at other positions acombination of motions of the control members 93, 94 is obtainedsubstantially in accordance with FIG. 6.

In one particular example the dimensions of the linkage are as follows,although it will, of course, be appreciated that other dimensions may beprovided as will be apparent to a person of skill in the art.

    ______________________________________                                               Dimension                                                                             mm                                                             ______________________________________                                               C       240                                                                   D       150                                                                   E       100                                                                   G        50                                                                   H        30                                                                   I       180                                                                   J        45                                                                   K       305                                                                   M        90                                                                   N        50                                                                   P       440                                                            ______________________________________                                    

The control force ratio between sideways movement of the control member95 and the forward and reverse movement can be varied by altering thelength of the links 99 which, in the illustrated example are 150 mmlong, which with a distance between the points A1, A2 in the neutralposition of the pumps of 240 mm gives a 45° angle between the links 98and the line joining the points A1, A2. By making the links longer theforce required for sideways movement of the member 95 will be greaterand the extent of sideways travel smaller and would give the controlmember 95 a bias towards straight line travel.

FIG. 8 illustrates an alternative hydraulic linkage in which thehydrostatic pumps and motors are as described in connection with theFIG. 7 embodiment and the input members 93, 94 again have input levers96, 97 respectively. However, the levers 96, 97 are connected to pistonrods 120, 121 of double acting hydraulic rams 122, 123 respectively. Thehydraulic rams 122, 123 are pivotally mounted to a part 124 of the body11 about vertical axes 125, 126 respectively which are parallel to theaxis of rotation of the input members 93, 94.

The piston rods 120, 121 are provided with piston heads 120a, 120b;121a, 121b respectively and the rams 122 are provided with correspondingcylinders 122a, 122b; 123a, 123b respectively which are provided withinlet ports 127a, 127b; 128a, 128b respectively.

Each input lever 96, 97 is associated with a centring lever 130, 131respectively which are pivotally mounted as shown at 132, 133 to a fixedpart 134 of the body 11.

The centring levers 130, 131 are pivotally biased together by coiltensions springs 135a, 135b and carry balls 136a, 136b; 137a, 137brespectively which engage abutment parts 138a, 138b; 139a, 139brespectively of the input levers 96, 97. If desired, instead of twosprings a single spring inter-connecting the levers 130, 131 may beprovided. The pivots 132, 133 are positioned so that when the inputmembers 93, 94 are in their neutral positions so that the swash platesare providing no output the abutment portions 138a, 138b; 139a, 139b areeach engaged by their associated ball 136a, 136b; 137a, 137b of theassociated centring lever 130, 131 so that the input members 93, 94 arebiased towards their neutral position from any displacement in eitherdirection therefrom and hence are normally maintained in their neutralposition in the absence of any input. It should be appreciated that theabove described centring means may be equally applied to the mechanicallinkage described with reference to FIG. 7 but has not been illustratedin FIG. 7 for clarity.

Referring now to FIGS. 9a and 9b, the propulsion control member 95 isuniversally mounted about a point P by a suitable universal joint 140 toa base part 141 which, in the present example, is fixed relative to thebody 11.

At its upper end the control member 95 has a knob 142 which can begrasped by the operator.

Adjacent the lower end of the member 95 is a valve operating surfacemember 143 which provides a part spherical valve operating surface whichis engaged by valve operating plungers 144-147 which are disposed atequal distances from the universal joint 140 and on planes containingthe point of pivot of the joint 140 and are equally angularly spacedtherearound lying in planes indicated at 45° to a line through the joint140 and parallel to the fore and aft axes of the vehicle.

The plungers 144-147 are spring biased into engagement with the surfacemember 143 and, in themselves, would tend to bias the member 95 into avertically upward position as shown in FIG. 9b with an equal bias toreturn the member 95 to the neutral position when displaced therefrom inany direction.

In order to provide a bias towards movement of the control member 95 ina forward and reverse direction two further spring bias plunger membersare provided as illustrated at 148 and disposed on opposite sides of theuniversal joint 40 on a line perpendicular to the fore and aft axis ofthe vehicle. The spring bias provided by the plungers 148 issignificantly stronger than that provided by the plungers 144 thus astronger bias to return the member 95 to the vertical occurs when themember 95 is displaced from the vertical to the left or the right thanwhen it is displaced from the vertical in a forward or reversedirection. This provides the vehicle with a bias towards forward andreverse movement of the member 95 with stronger operator force beingrequired to cause steering movement of the vehicle to the left or theright thereby facilitating forward or reverse driving of the vehicle andin addition making the vehicle safer.

The valve operated by the plunger 144 is arranged to feed hydraulicfluid under pressure when the plunger 144 is depressed to the port 127bof the ram 122 to cause the input member 93 to rotate clockwise toprovide forward drive to the left-hand propulsion unit. Similarly, theplunger 147 is arranged to cause its associated valve to feed fluid tothe port 128b of the ram 123 to cause the input member 94 to operate theright-hand propulsion unit in a forward direction.

Depression of the plunger 145 causes its associated valve to feed fluidto the port 128a of the ram 123 to cause the member 94 to rotate in ananti-clockwise direction and to cause the right-hand unit to drive inreverse, whilst depression of the valve member 146 causes its associatedvalve to feed fluid under pressure to the port 127a of the ram 122 tocause the member 93 to rotate anti-clockwise to cause the left-hand unitto drive in reverse.

When the member 95 is moved to the right plungers 144 and 145 aredepressed causing forward movement of the left-hand unit and reversemovement of the right-hand unit so that the vehicle spins on its axis tothe right. Similarly, movement of the member 95 to the left depressesthe plungers 146 and 147 to cause the left-hand unit to rotate inreverse and the right-hand unit to operate forward to cause the vehicleto spin on its axis in a left-hand direction.

When the lever 95 is moved at 45°, for example, at 45° between theforward and right directions, the valve 144 only is depressed so thatthe left-hand unit is caused to drive forward whilst the right-hand unitremains at its neutral position since neither of its operating plungers145 or 146 are depressed. A similar depression of only one plungeroccurs at each of the 45° positions with associated movement only of oneof the propulsion units in accordance with the regime of FIG. 6.Movement of the control member 95 to positions intermediate the 45°positions described hereinbefore causes a combination of movements inaccordance with the valve members which are depressed and their extentof depression.

In the above described hydraulic linkage system the maximum displacementpossible of the propulsion control member 95 in terms of its angularrotation about a horizontal axis passing through the point P varies inaccordance with whichever of the various directions in which it isdisplaced. For example, when the control member 95 is moved in aforwards direction so that the valve operating members 144 and 147 aredisplaced downwardly, then for a given extent of valve operating memberdisplacement the control member 95 will move forwardly further thanwould be the case if it were moved, for example, at 45° to the right sothat only the valve member 144 were displaced downwardly. This isbecause the radial distance of the line of action of the valve operatingmembers 144, 147 is closer to the axis of pivot of the member 95 than isthe valve operating member 144, thus the control member 95 is moved to agreater extent in each of the forward, reverse and left and rightpositions compared with intermediate positions at 45° therebetween andthe upper line in FIG. 6 illustrates this.

A similar differential in the extent of control member movement occurswith both the rigid mechanical linkage described above and the flexiblemechanical linkage now be be described.

Referring now to FIG. 10, there is shown an alternative mechanicallinkage utilising a pair of flexible push-pull cables 150, 151. An innermember 150a of the cable 150 is connected to the propulsion controlmember 95 so that forward movement, F, of the member 95 pulls the innermember 150a out of its outer case 150b whilst reverse movement Rv of thelever 95 pushes the inner member 150a relative to the outer member 150ball with respect to a neutral position of the lever 95. Similarly, theinner member 151a of the other cable 151 is connected to the member 95so that movement of the lever 95 to the left, L, from a neutral positionpulls the inner member 151a out of its outer member 151b whilst movementof the member 95 to the right R, pushes the inner member 151a into itsouter member 151b.

The outer members 151b and 151b of the cables 150, 151 are anchored, attheir ends adjacent the member 95 to a fixed part 152 of the body 11.

At its other end the outer member 150b is anchored to a fixed part 153of the transmission 21 whilst the inner member 150a at this other end ispivotally connected to a parallelogram linkage 154 at point A.

The outer part 151b of the cable 151 is anchored at its other end to theparallelogram linkage 154 at point B whilst the inner member 151a atthis other end is anchored to the linkage at point A.

The linkage comprises four equal-length links 155-158. The links 155 and156 are connected together at their one ends and to the inner members151a, 150a at point A. At its other end link 155 is connected to inputlever 96 at point C which is also connected to link 158 the other end ofwhich is connected to the outer member 151b at point B and alsoconnected, at this point, to link 157 the other end of which isconnected to input lever 97 at point D to which link 156 is alsoconnected.

In use, movement of the lever 95 in a forward direction, F, will pullthe inner member 150a through the outer member 150b so as to cause thepoint A of the linkage to move up right in FIG. 10 and hence to causeboth input levers 96, 97 to rotate clockwise to cause both pumps tocause forward drive of their associated propulsion means. Movement ofthe lever 95 from the neutral position in the rearward direction Rv willcause movement of the point A down in FIG. 10 and hence anti-clockwisemovement of the input members 93, 94. Movement of the lever 95 to theright, R, will cause movement of inner member 151a to move the point Ato the left to cause the input levers 96, 97 to rotate in oppositedirections so that the points C and D approach and hence so that inputmember 93 rotate clockwise to cause forward driving movement of theleft-hand propulsion unit, whilst the input member 94 rotatesanti-clockwise to cause reverse movement of the right-hand propulsionunit.

When the member 95 is moved to the left, L, from a neutral position thenthe member 151a will be moved to move the point A to the right so thatthe input levers 96, 97 will rotate in opposite directions away fromeach other so that input member 93 is caused to rotate anti-clockwise togive reverse drive at the left-hand propulsion unit whilst the inputmember 94 is caused to rotate clockwise to give forward drive to theright-hand propulsion unit.

When the lever 95 is moved to a position at 45° to any of the orthogonalpositions described hereinbefore, for example 45° to the right betweenthe forward and right positions, the linkage will move such that theoperating lever 97 of the pump to the right-hand propulsion unit willremain in its neutral position shown in FIG. 10 whilst the operatinglever 96 to the left-hand pump will be moved to its forward position anda similar combination of motions to achieve the regime shown in FIG. 6will be achieved for other directions of movement of the lever 95 in ananalogous manner to the motions described hereinbefore in connectionwith the other mechanical linkage and hydraulic linkage.

Motor and Stub Axle Mounting

The side members 18, 19 each comprise a loop case compartment and asbest shown in FIG. 4 each comprise a transversely inner wall 160 and atransversely outer wall 161 which are joined by top and bottom walls162, 163 and end walls 164, which provide an oil tight compartment.

It will be seen that the outer walls 161 provide main chassis members ofthe vehicle body and that at the rear of the vehicle extensions of theouter walls provide the inner side plate of the upstanding members 26,27. In addition, a transversely extending member 165 interconnects themain chassis members 161 together and provides a floor to the body.

The loop case compartments 18, 19 have mounted thereon, at the positionsshown in FIG. 2 and FIG. 1 respectively, the ground engageablepropulsion wheels 15, 16 and the motors 92.

Referring now particularly to FIG. 11, there is illustrated the mountingof one of the ground propulsion wheels 16 on the loop case compartment18 although it should be appreciated that each of the four wheels ismounted on its associated loop case compartment in exactly the samemanner and do not require separate description.

At the location of the wheel 16 the outer wall 161 is provided with acircular opening 166 which provides a first guide means whichco-operates with a second guide means provided by a shoulder 167 of acarrier member 168 of generally frusto-conical configuration and formedintegrally with a stub axle housing member 169. The stub axle housingmember 169 carries taper roller bearings 170 so that a stub axle 171 ishoused by the member 169 so as to be rotatable about an axis of rotation172.

The wheel 16 is bolted to one end of the stub axle 171 in conventionalmanner by bolts 173 whilst a driven wheel in the form of a sprocket 174is bolted to the other end of the stub axle 171 by bolts 175.

The stub axle and its housing, together with the carrier member 168 areconfiguration so that the sprocket 174 is disposed within the loop casecompartment 18. The teeth of the sprocket 174 are offset from a centralmounting part of the sprocket so that the sprocket can be fastened tothe stub axle 171 in a reverse orientation, shown in chain line in FIG.11, when attached to the stub axle for the other wheel on the same sideof the vehicle.

The carrier member 168 is formed so that the axis of rotation 172 of thestub axle 171 is eccentrically disposed relative to the central axis ofthe rebate 167 and hence relative to a reference axis 176 about whichthe carrier member 168 is guided to rotate by co-operation between thehereinbefore mentioned guide surfaces 166, 167.

Clamping means, such as an annular ring 177, are provided to enable thecarrier member 168 to be clamped to the outer wall 161 in any desiredangular orientation around the reference axis 176.

By the above described eccentric disposition of the axis 172 relative tothe axis 176, the position of the axis 172 both longitudinally andvertically of the vehicle can be adjusted thereby permitting ofadjustment of the wheel base of the vehicle, in association with drivingchains of appropriate lengths, as well as permitting of adjustment ofthe ground clearance of the vehicle together with providing a facilityfor tensioning a chain of a given length.

It will be seen that the stub axle 171 is supported solely from the sidewall 161 without any support being afforded by the inner wall 160thereby avoiding the need to effect any machining operations on the wall160 which would otherwise be necessary if the stub axle wereadditionally supported thereby.

In addition, a clearance is provided between the sprocket member 174 andthe wall 160 to permit of manipulation of a chain through the space andhence into driving relationship with the teeth of the sprocket 174.

Referring now to FIG. 12, there is shown the mounting of a motor 92 onthe loop case compartment 18.

The motor 92 is a conventional commercially available high torque motorand has a conventional output shaft 180. The motor 92 has a mountingflange 181 by which it is bolted to a mounting plate 182 welded to theinner wall 160 of the compartment 18. The mounting plate 182 has arebate 183 which is received within a circular aperture 184 formed inthe wall 160 to aid location of the ring 182.

A sleeve 185 is machined to provide a pair of driving wheels in the formof sprockets 186, 187 and an inner part 188 of the central passage ofthe sleeve 185 has the output shaft 180 received therein with a splinedconnection 189 provided therebetween.

A seal 186a is provided in the central passage and a shaft seal 186b isalso provided so that lubricating oil for the splined connection 189supplied from the motor 92 is caused to flow via bore 186c to lubricatethe bearing 190 before returning to the motor.

A taper roller bearing 190 is provided between the external surface ofthe sleeve 188 and a seat 191 provided by the body 192 of the motor 92.

A bracket member 193 in the form of a three-legged spider is bolted tothe pump body 192 by bolts 194, only one leg 195 and one bolt 194 beingshown in FIG. 12, the other two legs and bolts being equally angularlydisposed around the axis of rotation of the output shaft 180A furthertaper roller bearing 196 is provided between the bracket 193 and anouter surface part of the sleeve 185.

A brake drum 197 is formed with a boss 198 which is received within anouter part 199 of the central passage of the sleeve 185 and is retainedin splined engagement therewith, as shown at 200 by a bolt 201. Thesleeve is provided with a transversely extending passage 202 to receivea locking pin for the bolt 201.

Chains, such as roller chains, not shown, are looped around therespective sprockets 186, 187 and the respective driven sprockets 174and the sprocket, not shown, of the other wheel.

To assemble the sprocket and chain drive, initially the chains aremanoeuvred into the compartment 18 through an opening 203 provided inthe outer wall 161 and are passed between the inner wall 160 of thecompartment 18 and the respective driven sprocket such as the sprocket174. At this stage, although the motor 92 is bolted in position, thesleeve 185 and bracket 195 are absent.

The sleeve 185 is then offered up the outward shaft 180 and the chainsare then manoeuvred over the outer end of the sleeve 185 and intoposition on their associated sprockets 186, 187. The hereinbeforedescribed eccentric mounting of the stub axles permits the stub axleaxes 172 to be moved towards the motor 92 to provide sufficient slack inthe chain for the above manipulation to occur.

The bracket member 195 is then bolted in position with the chainspassing through the spaces between the legs 195 thereof. Thereafter thebrake drum 197 is bolted in position and finally an extension housingenclosure member 204 is bolted in fluid tight relationship to the outerwall 161.

In the assembly described with reference to FIG. 12, the output shaft180 and the associated driving sprockets 186, 187 and brake drum 197 aresupported entirely from the motor through the bracket 195 and receive nosupport from any component which is independent of the motor and inparticular do not receive any support from the outer member 161. It istherefore unnecessary to perform any machining operation on the member161 other than the simple information of the clearance opening 203 whichmay be made, for example, by flame cutting.

If desired, the motor described above may be mounted on the outer wall161 instead of the inner wall.

Instead of driving the stub axles from a shaft motor through loops, ifdesired, the stub axles may be driven by other means such as, byproviding a separate motor which may drive each stub axle directly. Inthis case, if desired the above described eccentric mounting may also beprovided with the motor similarly moving eccentrically with the stubaxle.

Operator Restraint

Referring now to FIGS. 13-15, a restraint member 210 is provided whichis mounted on the body by a lever 211 for movement between operative andinoperative positions. The operative position is shown in FIG. 13 and inthis position the member extends transversely of the operator'scompartment 22 in restraining relationship with the seat 23 so as torestrain an operator seated on the seat accidentally falling forwardsshould, for example, the vehicle come to a sudden halt or tip forwardly.The inoperative position is shown in FIG. 14 in which the lever 211 hasmoved from the generally upwardly position it occupies when therestraint member 210 is in its operative position to a generallyforwardly extending position so that the restraint 210 and lever 211 aredisposed so as to permit of passage of an operator into and out of theseat 23 through the access opening 33.

The lever 211 is pivoted to the body 11 by suitable pivot means, aboutan axis 212 which extends transversely of the vehicle. A rigid strut 213is pivotally connected to the lever 211 at one end and is provided witha ratchet which may engage a ratchet member to lock the lever 211 in itsoperative position, as hereinafter to be described in more detail withreference to FIG. 15.

In the embodiment illustrated in FIGS. 13 and 14 restraint member 210extends in cantilever from the lever 211. The lever 211 also carries anarm rest element 214 which pivots with the lever 211 and restraint 210.On the opposite side of the operator's compartment hereinbefore referredto as the "one" side 31 a fixed arm rest element 215 is provided whichis fixed relative to the seat 23 and the restraint 210 has a rearwardlydirected part 216 which co-operates with the fixed arm rest element 215so as to fully restrain the operator.

In the embodiment shown in FIGS. 13 and 14 the propulsion control member95 of the hereinbefore described mechanical rigid linkage is providedand hence is mounted on a fixed part of the body 11 and so, as shown inFIG. 14, does not move with the lever 211 but as it is disposed on saidone side 31 of the body it does not interfere with access of an operatorthrough the access opening 33 on said other side 32 of the body.

Also provided on said one side of the compartment mounted on a fixedpart of the body is a speed control 217 for the engine.

The lever 211 carries the manually operable loader control 25 whichoperates the valve means as described hereinbefore, the valve meansbeing connected to the lift and implement operating rams by flexiblehydraulic pipes which pass down the lever 211 and exit therefromadjacent its lower end and pass to their associated rams. The flexiblepipes, of course, permit of the hereinbefore described pivotal movementof the lever 211.

Referring now to FIG. 15 which shows a modification of the restraintshown in FIGS. 13 and 14. In this modification the restraint 210 issupported not only by a lever corresponding with the lever 211 describedhereinbefore but, in addition, at the opposite end thereof by a secondsimilar lever 211a which is pivotally mounted about the same axis 212 asthe lever 211 and which carries a further arm rest element 214a. Asshown in FIG. 15 the rigid strut 213 is provided with ratchet teeth 218which co-operate with a ratchet member 219 which is provided with aco-operating guide 220 to constrain the link 213 from excessive pivotalmovement away from the ratchet 219. In addition the link 213 has atransversely extending lug 221 at its lower end which can be engaged bya foot of the operator to enable him to pivot the link 213 upwardly outof engagement with the ratchet 219 to permit of movement of therestraint from an operative to an inoperative position. Alternatively aratchet mechanism operated by a trigger or other manually operablemechanism on or adjacent the restraint may be provided. Such movement isaided by providing gas springs 222 of conventional type.

The lever 211a carries the propulsion control member 95 of the kind usedwhen the linkage is the hydraulic of flexible mechanical linkagedescribed hereinbefore. In either case the flexible hydraulic pipes ormechanical push-pull cables permit of pivotal movement of the lever 211aabout the pivot 212.

If desired, the control means 95 may be mounted on a fixed part of thebody irrespective of the linkage and the restraint 210 may be in thatcase supported by either a single lever as shown in FIGS. 13 and 14 orby two levers as shown in FIG. 15.

The link 213 and gas springs 222 described and illustrated withreference to FIG. 15 also provided in the embodiment shown in FIGS. 13and 14.

In addition, in both embodiments a flexible cable or rigid mechanicallink is provided between the or at least one of the levers 211 and aparking brake of the vehicle. Such a link is shown at 223 in FIGS. 13and 15.

Although in the illustrated examples the propulsion control lever 95 hasbeen described as being on said one side 31 of the operator'scompartment whilst the loader control means 25 has been disposed on saidother side 32, if desired the location of the said controls can betransposed consistent with the linkage from the propulsion control beingcapable of accommodating pivotal movement of the lever 211.

In use, the link 223 ensures that the vehicle parking brake is off whenthe restraint 210 is in its operative position and is applied when therestraint 210 is in its inoperative position. In addition an interlockto the engine is provided, not shown, which with the restraint 210 inits operative position enables the engine to be continued to run andalso enables the engine to be started but, in each case, only if anoperator is sitting on the seat since an additional interlock isprovided sensitive to the presence or absence of an operator.

When the restraint 210 is moved to an intermediate position from itsoperative position the interlock senses this and causes the engine to beimmobilised.

When the restraint 210 is in its inoperative position the interlockpermits the engine to be started and in this case the engine can bestarted even if an operator is not in the seat but only if the parkingbrake is applied by virtue of the link 223.

The ratchet teeth 218 are positioned and provided so as to permit ofadjustment of the restraint 210 when in an operative range of positionsto suit different sizes of driver.

Operator's Compartment

The operator's compartment 22 is defined in part by the inner plates26a, 27a of the upstanding members 26, 27, the roof 28 and the posts 29which together provide the enclosure with one side, 31 and a top andrear wall which include means for preventing access therethrough. In thecase of the one side 31 this is by virtue of the presence of the boomassembly and also the wire mesh protective screen 30. At the rear, theoperator's compartment is defined in part by the front wall 34b of theengine compartment 34. The space between the top wall 34b and theunderside of the pivot member 42 whilst preventing access to theoperator's compartment does permit the operator to look out of thecompartment to the rear beneath the pivot member 42.

The inner plates 26a, 27a which in substance define part of theoperator's compartment are themselves integral continuations of theouter walls 161 of the hereinbefore described side members 18, 19. Inthe present example the inner plates 26a, 27a, and a contoured base 28aare made by bending a single plate to the profile shown in FIG. 4. Theroof 28 is welded to the plates 26a, 27a. If desired the operator'scompartment may be integrated with other structural members of the bodyby welding instead of being formed from a single plate.

This it will be seen that the main structural parts of the operator'scompartment which provide the wall thereof are formed integrally withother structural elements of the vehicle and in particular the sidemembers 18, 19 which provide the loop cases and the upstanding members26, 27 which carry the boom assembly pivots and thus the operator'scompartment is integrated with the remainder of the machine and hencehas a high ability to withstand forces exerted thereon during roll-overconditions.

The features disclosed in the foregoing description, or the accompanyingdrawings, expressed in their specific forms or in the terms or means forperforming the desired function, or a method or process for attainingthe disclosed result, may, separately or in any combination of suchfeatures, be utilised for realising the invention in diverse formsthereof.

I claim:
 1. A skid steer vehicle comprising a body having a front endand a rear end and ground engageable propulsion wheels disposed onopposite sides of the body, a stub axle for each propulsion wheel, eachstub axle having an outer end on which a said propulsion wheel iscarried, a stub axle housing member for each stub axle, means to house astub axle in each stub axle housing member for rotation of the stub axlerelative to the housing member about an axis of rotation, a carriermember provided for each stub axle housing member, the carrier memberand the body being provided with co-operating guide means to guide thecarrier member for rotation about a reference axis, means to mount eachcarrier member on the body in a selected one of a plurality of anyangular positions about said reference axis, the stub axle housingmember being positioned relative to the carrier member so that said axisof rotation is disposed eccentrically relative to said reference axis.2. A vehicle according to claim 1 wherein each stub axle has an innerend and a flexible loop is drivingly engaged with said driven wheel andwith a driving wheel drive by a motor.
 3. A vehicle according to claim 1wherein clamping means are provided to clamp the carrier member in saidselected position relative to the body.
 4. A vehicle according to claim1 wherein the body is provided with an engine, two pairs of groundengageable propulsion wheels disposed on opposite sides of the body, ahydraulic drive means including first and second variable displacementpumps driven by the engine and operatively connected to first and secondhydraulic motors disposed on opposite sides of the body, each motorbeing drivably connected to two ground engageable propulsion wheels ofan associated one of said pairs of wheels on the associated side of thebody by first and second endless loops each of which is engaged with adriving wheel driven by the motor and with a driven wheel connected toan associated one of the ground engageable wheels of said pair andpropulsion control means whereby the hydraulic drive means can drive thepair of wheels on one side of the vehicle at a different speed anddirection from the pair of wheels on the other side of the vehicle topropel and steer the vehicle.
 5. A vehicle according to claim 1 whereinthe body is provided with a longitudinally extending loop casecompartment on each side of the vehicle, each loop case compartmenthaving a transversely inner wall and a transversely outer wall joined bytop and bottom walls and end walls, said stub axle housing member ormembers being mounted on the outer wall with said driven wheels disposedwithin said compartment.
 6. A vehicle according to claim 5 wherein twostub axle housing members are provided on each side of the vehicle andeach of said housing members are mounted on said outer wall with saiddriven wheels disposed within the compartment with said driving wheelsdisposed within the compartment therebetween with said loops engagedwith respective driving and driven wheels.
 7. A vehicle according toclaim 5 wherein the outer wall is provided with a circular opening foreach housing member to provide one of said co-operating guide means. 8.A vehicle according to claim 2 wherein each driving wheel is carried onan output shaft of a motor and is unsupported by means independent ofthe motor.
 9. A vehicle according to claim 8 wherein the body isprovided with a longitudinally extending loop case compartment on eachside of the vehicle, each loop case compartment having a transverselyinner wall and a transversely outer wall joined by top and bottom wallsand end walls, said stub axle housing member or members being mounted onthe outer wall with said driven wheels disposed within said compartmentand each motor is mounted on one of said inner and outer walls of anassociated loop case compartment with each driving wheel disposed withinthe associated loop case compartment.
 10. A vehicle according to claim 9wherein each driving wheel is carried on an output shaft of theassociated motor and is unsupported by a wall of the associatedcompartment opposite to the wall on which the motor is mounted.
 11. Avehicle according to claim 10 wherein the output shaft of each motor issupported at an outer part thereof by an outer bearing carried by abracket fastened to the respective motor body.
 12. A vehicle accordingto claim 11 wherein the bracket is provided with openings to permitpassage of said loop.
 13. A vehicle according to claim 12 wherein eachdriving wheel is provided on a sleeve member which receives the outputshaft of the associated motor therein at one end, an inner bearing beingprovided between the sleeve and the body of the motor.
 14. A vehicleaccording to claim 13 wherein the outer bearing is provided between thebracket and said sleeve.
 15. A vehicle according to claim 13 wherein abrake member is carried by the output shaft outwardly of said sleeve.16. A vehicle according to claim 9 wherein the outer wall of each loopcase compartment is provided with an opening adjacent the motor anddriving wheel to permit manipulation of a loop into driving relationshipwith a driving wheel and driven wheel.
 17. A vehicle according to claim15 wherein the brake member is disposed outwardly of the part of theouter wall of the loop case compartment at locations spaced from saidmotor.